1. Technical Field
The invention relates to a cover for sealing an opening in a weatherproof roofing membrane. More particularly, the invention relates to a cover and to the method of applying it over a mechanical fastener or T-joint of a weatherproof roofing membrane to seal an opening therein.
2. Background Information
A large number of commercial and factory plant roofs are of a flat roof design wherein the roofing material itself is often of a built up asphalt, and in more modern systems is a single ply of an elastomeric sheet material or membrane, acrylic, or similar weatherproof sheeting, which utilizes a mechanical ballast system or layer of stone over the membrane. While the ballast system is preferable for certain installations, it has a disadvantage of being heavier and is not suitable for steeper roof slopes.
Other membrane systems use mechanical fasteners which require fixation of components to the roofing substrate via mechanical fasteners. There are two basic kinds of mechanical fastening systems, namely membrane penetrating and non penetrating types. Each of these types of systems has a number of favorable features, and each of them is subject to various drawbacks and disadvantages. One type of non penetrating roof membrane fastening system is shown in U.S. Pat. No. 4,852,323. A penetrating type of fastening system is shown in U.S. Pat. No. 4,620,402. One disadvantage with the penetrating type fastening system is that the membrane is pierced providing a possible area of water leakage.
In the installation of membrane roof coverings, the membrane is unrolled in relatively large sheets of the weatherproof membrane which may have widths of 6, 8, 10 feet or more and lengths of up to 100 feet. These sheets when laid out over a roof deck are spliced together to form a continuous roofing sheet. The linear seams are formed by lap joints or butt joints and are spliced to adjacent sheets where the edges are abutted or overlapped. In certain applications, a third sheet may overlap the joint of the other two sheets and form a T-joint, which due to the unevenness of the lapped joint provides a possible opening through which water could seep to the lower roof deck.
It is desirable that a cover or patch be provided for these T-joint areas as well as for the penetrating mechanical fasteners for certain roof membrane covering systems. Typical membranes for such installations are formed of reinforced or nonreinforced EPDM (ethylene propylene diene copolymer) or neoprene, and certain acrylics or plastic materials.
Various types of sealing tapes have been devised to seal the seam between adjacent roofing membranes. A known two layer sealing tape construction consists of an upper layer containing vulcanized EPDM and reinforced resin, in combination with a lower layer of sealing tape material. However, these prior art sealing tapes do not for certain applications provide the desired sealing affect which can in turn cause leaks in the openings in the roof membranes provided by the T-joints and mechanical penetrating fasteners.
Various other types of covers or patches also have been devised for various types of sealing applications, known examples of which are set forth in the following patents.
U.S. Pat. No. 3,049,836 discloses a roof repair patch comprising a shallow inverted pan-like shell containing a mastic composition in the upper portion of the shell and a membrane underlying the mastic composition.
U.S. Pat. No. 3,111,787 shows a roofing element consisting of a top layer of felt and adhesive, and a release paper for attachment to a plywood roof deck.
U.S. Pat. No. 4,135,017 discloses a laminated patch for repairing a hole in a surface of an interior wall. A rigid plate of aluminum is covered with an adhesive on one side for bonding it to the wall surface, which adhesive is initially protected by a release film.
U.S. Pat. No. 4,358,495 discloses a dry wall patch kit consisting of a pair of disc shaped members, one of which is larger than the other to provide a peripheral bonding area.
U.S. Pat. No. 4,437,283 discloses a sealing tape having an adhesive on both sides, in combination with a cover member formed of the same material as the roofing member, such as EPDM. The tape also has a removable adhesive release liner, and due to the double sided adhesive, adheres to both the roof membrane as well as to the covering membrane to provide a seal therefore.
U.S. Pat. No. 4,602,971 shows a patch consisting of a carrier layer having an outer circular patch layer secured thereto by an adhesive. An inner circular barrier layer which is free of any adhesive is located within the surrounding adhesive layer.
U.S. Pat. No. 4,657,958 discloses one type of an adhesive composition for bonding sheets of EPDM elastomeric roofing membranes to each other on a roofing system.
U.S. Pat. No. 4,732,635 discloses a method of making spliceable sheet material in which polyethylene film is adhered to one border of a cured EPDM member having an adhesive with a protectable removable liner, which when assembled is subjected to heat and pressure to cure the compound and bond the heat sealable adhesive to the adjacent membrane.
U.S. Pat. No. 4,757,652 discloses a type of shingle having release sheets on edge portions of the underlying surfaces thereof whereby the bitumen material of the shingle will adhere to adjacent shingles after removal of the release sheet.
U.S. Pat. No. 4,767,653 discloses a heat sealable sheet material for use in the formation of lap seam membranes in which polyethylene film is adhered to the border of the cured EPDM material. The resulting assembly then is subjected to heat and pressure to cure the compound and bond the membrane to the heat sealable adhesive.
U.S. Pat. No. 4,855,172 shows a laminate system consisting of a cover strip having an adhesive layer applied to a strip of the roofing membrane material in combination with a fastening bar.
U.S. Pat. No. 4,936,071 discloses a seaming tape for metal roofing which also can be used as a patch. This cover consists of a top layer of EPDM and a bottom layer of butyl rubber which enables the top layer of EPDM to be firmly secured to the bottom layer due to the natural tackiness of the bottom layer. A protective release sheet or silicone treated paper also is provided to protect the tacky layer until ready for use.
U.S. Pat. No. 4,972,638 shows an EPDM flashing used for sealing skylight windows, which is provided with an adhesive on one side.
Although a number of the above discussed prior art sealing tapes and patches are effective for their intended installation, they may not be suitable for the exposure to which the cover of the present invention is subjected to when used on an exposed roofing membrane. In such an environment the cover is subjected to wide ambient changes in temperature and to physical and chemical abrasion, and to harmful ultraviolet rays, due to the environment in which it is utilized. Furthermore such prior art covers do not provide the desired flowability so that the sealing material can flow into openings to provide an effective seal therefore without requiring time consuming installation procedures and additional material components.